Interfacial Synthesis of Cs ₂ PtCl ₆ Perovskite for Strong Coupling with V ₄ C ₃ T _x MXene Toward Efficient Hydrogen Evolution and Urea Oxidation

A key innovation in this work is the development of a trapping method to synthesize perovskite Cs₂PtCl₆ nanoparticles at a liquid-liquid interface under ambient conditions. The resulting nanoscale Cs₂PtCl₆ particles are able to combine with various MXenes via PtCl₆ ^2- units, among which V₄C₃T_X MXene forms strongly coupled Cs₂PtCl₆@V₄C₃T_X composites. Cs₂PtCl₆@V₄C₃T_X exhibits excellent hydrogen evolution reaction (HER), delivering a dramatically reduced overpotential of ∼39 mV a current density of 10 mA cm^- ², which outperforms the pristine V₄C₃T_X, Cs₂PtCl₆, and other Cs₂PtCl₆@MXenes composites investigated. On the other hand, Cs₂PtCl₆@V₄C₃T_X exhibits negligible oxygen evolution reaction, but remarkably high-performance urea oxidation reaction. The selective anodic reactivity simultaneously reduces the overall energy input required for HER. Comprehensive studies with other MXenes and their Cs₂PtCl₆ hybrids highlight the unique and critical role of V₄C₃T_X in facilitating electron transfer and catalytic stability, paving the way for simultaneous production of clean energy and remediation of organic pollutants.